There exist many types of filters for removing particulate matter from an influent. Such filters are generally classified as the type having either a bonded media or a nonbonded media. A filter that employs a bonded media generally includes either a removable cartridge element constructed of a fibrous woven or nonwoven material, or includes a membrane that has very fine pore size openings.
Another family of filters employs a nonbonded media, which are basically of two types. The conventional nonbonded granular type filter is well known, and a much newer radial flow filter using a nonbonded media is described in U.S. Pat. Nos. 6,322,704; 6,852,232; 7,163,621 and 7,470,372, all by Martin.
Eventually the filters employing either a bonded or nonbonded medium become plugged with contaminants and must be cleaned or replaced. The replacement of the filter elements is effective to restore the filter operation, but can be expensive and time consuming.
In the case of a nonbonded media filter, the media itself can be regenerated through either fluidization to purge the granules or beads of particulate matter accumulated in the interstices of the media. However, and most importantly, the retaining screens that contain the nonbonded media can also become plugged over time and need to be cleaned, as the fluidization process does not always clean the screens sufficiently. Therefore, over time the screens must either be replaced or disassembled and cleaned. An expensive alternative is to replace the retaining screens with new, clean retaining screens, although this is expensive and time consuming.
In the case of conventional bonded cartridge type filters, the cartridge must be manually cleaned or replaced after a period of operation. The cleaning of the cartridge of a filter generally involves removal of the cartridge, and manually spraying the outer surface to remove the residue collected thereon.
From the foregoing, it can be seen that a need exists for a method and apparatus to cleanse a radial-flow filter, whether it be the conventional cartridge or the newer nonbonded type. In the case of the conventional cartridge or the generic filter screen, the life can be extended, often dramatically, by eliminating the filter cake buildup on the inside or outside of the filter. In the case of a filter employing a nonbonded filter medium, the filter medium itself can be regenerated by a fluidizing operation, but the buildup on either the outside or inside retaining screens can become clogged with residue which requires removal to restore the operation of the entire filter.